MICROELECTROMECHANICAL ACCELEROMETER DEVICE

摘要

The structure enables two-directional sensing of accelerations with compact component dimensions and with minimal cross-axis sensitivity. The rotation mass includes a first frame and a second frame. In one sense direction, the structure employs a combined proof mass of the first frame and the second frame, which improves the signal to noise level achievable with said device dimensions. In the other sense direction, a detection structure with at least two sensing elements is used to detect displacements of the proof mass of the second frame. Due to the specific internal configuration of the detection structure, signal contributions of the sensing elements in the one direction cancel each other.

主权项

1. A microelectromechanical structure for measuring accelerations, which microelectromechanical structure comprises:
a rotor mass including a first frame and a second frame; a first spring structure for suspending the first frame into a neutral position from a support plane, wherein the first spring structure responds to displacements of the first frame from the neutral position along a first in-plane direction with stiffness of a first spring constant, and eliminates displacements of the first frame along directions other than the first direction; a primary detection structure for detection of displacements of the rotor mass from the neutral position along the first direction; a second spring structure for suspending the second frame into a neutral position from the first frame, wherein the second spring structure responds to displacements of the second frame from the neutral position along a second direction with stiffness of a second spring constant, and eliminates displacements of the second frame from the first frame along other directions than the second direction, the second direction being perpendicular to the first direction; a secondary detection structure for detection of displacements of the second frame, a signal of the secondary detection structure including a first signal component responsive to displacements of the second frame along the first direction and a second signal component responsive to displacements of the second frame along the second direction; the secondary detection structure includes at least one secondary detection element in which a pair of secondary sensing elements are positioned such that a displacement of the second frame along the first direction increases contribution of one secondary sensing element of the pair of secondary sensing elements to the first signal component, and decreases equally contribution of the other secondary sensing element of the pair of secondary sensing elements to the first signal component, the contribution of the one secondary sensing element of the pair of secondary sensing elements to the first signal component, and the contribution of the other secondary sensing element of the pair of secondary sensing elements to the first signal component thereby cancelling each other.